Employees of postsecondary technical schools governed by the department shall serve in the unclassified service of the state merit system as defined by Code Section 45-20-6, provided that employees who serve in the classified service of the state merit system as defined by Code Section 45-20-6 may elect to remain in the classified service, and be governed by the provisions thereof; provided, further, that such employees who choose to be promoted to unclassified positions or who request to transfer to different positions or locations shall become members of the unclassified service.